A general strategy for controlling infectious pathogens in humans and animals is the application of antibiotics, of which several thousand different compounds have been isolated and used to date. However, as a rule, their antibiotic activity is limited to only a few closely related pathogen species. In addition, an increasingly growing problem in the use of antibiotics is the occurrence of resistant bacteria [J. Davies, Science 1994, 264, 375–382; Inactivation of antibiotics and the dissemination of resistance genes]. The spreading of resistant bacteria takes from 2 to 5 years as a rule, so that there is a strong need to find or develop new efficient antibacterially effective agents. Attempts are also made to recover and employ so-called natural antibiotics; these are peptides or proteins which can be recovered from those organisms which come into contact with bacteria, i.e., from plants, lower and higher animals and humans. Although some natural antibiotics have been isolated and characterized, it has not been successful to date to develop them further to clinical use [J. E. Gabay, Science 1994, 264, 373–374; Ubiquitous natural antibiotics].
Now, it has surprisingly been found that compounds having antibiotic activity can be recovered from certain West-African snail species, namely snails of the genus Archachatina (especially the species A. marginata, A. degneri and A. ventricosa) and members of the genus Achatina with the species A. achatina, A. monochromatica and A. batteata. Inter alia, a protein isolated and identified from the yellowish mucus of the foot soles of these snails can be employed against a broad range of infectious pathogens.